I know T@D sent a gage with my paired shaft rockers to mill the stands to the proper height from the valve tip and they are valve lift specific.
Unless they changed something recently, I believe the tool is for a certain valve lift, and then the instructions tell you how much to adjust the height for a different valve lift from that starting point. One tool will not be correct for every valve lift was the point I was making. It is only to give you an "in the ballpark" starting point. If you press Jesel, they will tell you the same thing.